<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .parent{
            width: 500px;
            margin-left: auto;
            margin-right: auto;
            display: flex;
            flex-wrap: wrap;
            background: pink;
            justify-content: space-between;
        }
        .parent>div{
            width: 200px;
            height: 200px;
            border: 1px solid #333;
        }
    </style>
</head>
<body>
    <!--
        display:flex;
        flex-direction;
        控制子元素水平对齐的方法
        justity-content
        控制子元素垂直对齐的方法
        align-items
        子元素是否换行
        flex-wrap
    -->
    <div class="parent">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
</body>
</html>